Flexural vibration piece and oscillator using the same

A flexural vibration piece comprising:

• a flexural vibrator that has a first region on which a compressive stress or a tensile stress acts due to vibration and a second region having a relationship in which a tensile stress acts thereon when a compressive stress acts on the first region and a compressive stress acts thereon when a tensile stress acts on the first region, and performs flexural vibration in a first plane;
• an excitation electrode to vibrate the flexural vibrator;
• an external connection electrode connected the excitation electrode;
• and
• a heat conduction path, in the vicinity of the first region and the second region, that is formed of a material having a thermal conductivity higher than that of the flexural vibrator and thermally connects between the first region and the second region, wherein
• the heat conduction path is connected to the excitation electrode and the external connection electrode,
• when m is the number of heat conduction paths, αth is the thermal conductivity of the heat conduction path, αv is the thermal conductivity of the flexural vibrator, tv is the thickness of the flexural vibrator in a direction orthogonal to the first plane, and tth is the thickness of the heat conduction path, a relationship of tth≧(tv/m)×(αv/αth) is satisfied.